(a) Field of the Invention
The present invention relates to an improved jib assembly including a planetary gear reducer for the rotation of the assembly and for connecting same to an articulated boom.
(b) Description of Prior Art
A jib assembly generally of the type disclosed herein is described in Canadian Pat. No. 1,198,691 issued Dec. 31, 1985. The jib assembly as described in that prior art patent has disadvantages which the present invention overcomes. One main disadvantage of the prior art jib construction is that the jib is supported far from the boom thereby requiring a longer bucket support shaft as the jib is interposed between the bucket and the boom. Such long support shaft is subjected to heavier stresses due to its length. If two buckets are mounted on opposed sides of the same articulated boom, then one of the work persons is far, this away from the jib and to the increased spacing. A jib is usually used as boom for supporting or lifting heavy objects and is manipulated by a work person(s) occupying the bucket or buckets. The jib rotation drive disclosed in this patent is a worm gear arrangement using very high gear ratios, greater than 15:1, and thus adds to the considerable size and weight of the coupling. Also, the gear reduction unit is located outside the articulated boom and could be hazardous when located close to electrical transmission lines.